Colombo - Sri Lanka wants to use the forthcoming series against the Proteas as a stepping stone toward the No. 1 spot in the one day international rankings, ahead of next year's World Cup.
"That's at the back of our mind," Sri Lanka captain Angelo Mathews said of the top spot ahead of a three-match series against the Proteas.
"But we just want to take it game by game, series by series, play positive cricket."
Sri Lanka will play three ODIs and two Test matches against South Africa.
The first ODI is on Sunday in Colombo.
Sri Lanka is presently third in the ODI rankings, while South Africa is fifth.
Australia is the top ranked country.
Proteas captain AB de Villiers, said the upcoming tour would be tough due to the hosts' "great form".
Sri Lanka won the World Twenty20 tournament this year and has returned from a successful tour in England where it beat the home side in all three forms of the game.